Het is niet alleen I will.
Maar het is ook de afkorting van I shall.
I shall - I shall be in London tomorrow. = I'll
you will - You will see a large building on the left. = You'll
Plural [ meervoud]
we shall - We shall not be there when you arrive. = We shan't
you will - You will find his office on the 7th floor. = You'll
they will - They will arrive late. = They'll